Theatre: Who Shall Be Happy...? The Bush, London

The French Revolutionary leader, Georges Danton, is no stranger to stage or celluloid. In his greatest theatrical incarnation, as the hero of Danton's Death by Buchner, he's perceived as a world-weary Titan who, bored with the Revolution and with life, finally espouses a fatalistic view of history and harbours too great a contempt for his enemies to destroy them with their own grubby weapons.

As an historical figure, Danton is rich in ambiguity, viewed by some commentators as a generous realist never led astray by ideological absolutism, and by others as an opportunist whose bribe-taking flexibility sullied the honour of the Revolution. In Who Shall Be Happy...?, a powerful 80-minute two- hander staged now by its author, Trevor Griffiths, at the Bush, Danton, incarcerated in a Parisian prison cell at the height of the Great Terror, is presented as a man bitterly dismayed at the course of the Revolution: its outlawing of doubt; its continued violent discrimination between "them" and "us"; and its reliance on an "Empire" of expensively falsified images.

At times, this Danton peers directly at us, the "little white faces in the dark", and addresses us as the posterity which he believes will itself be imprisoned within the walls of cant and lies the Revolution is in the process of building. But all, according to him, is not lost, for though Liberty, Fraternity and Equality may wither, Hope, thanks to the Revolution, is now permanently on the human agenda. Stirring stuff, but true? You could, after all, argue the converse: that if you are keen on hope, then it's religion not revolutionary secularism that offers the best bet, since in the former case, hope is conveniently impervious to evidence and reason.

Griffiths's Danton, wonderfully well played by Stanley Townsend as a great sardonic bull of a man with a deflating Irish burr, concedes that "Our lives are very much like the theatre ... indifferently written and scandalously short of rehearsal." For him, in these crucial days, more so than most. Politics as theatre becomes a literal business, because the Committee of Public Safety has tried to bamboozle anyone thinking of springing this former hero from prison by planting a second "Danton", a lookalike decoy on loan from an asylum. Endeavouring to win the confidence of his guard (through whom he wants to convey a coded letter to his supporters), the real Danton has to persuade Kulvinder Ghir's suspicious, cannily self-preserving Henry, that he is the impostor. His ability to imitate the genuine article so accurately comes from once having researched him for a stage representation. He's the frog, he says, who swallowed the prince.

The predicament of a man pretending to be a fraud while inwardly remaining true to all his better instincts envelops the play in an irony that is never underlined too heavily. I did not see the television version of this piece, but the governing metaphor, viewed here, seems inherently of the theatre. With his last stage work, Thatcher's Children, one of the best post-war dramatists produced one of the worst post-war plays. Who Shall Be Happy...? is a heartening return to form.

To 29 June (0171-743 3388)